The invention relates to vapor compression systems and, more particularly, to performance enhancement in air conditioning systems utilizing economizer cycles.
Economizer cycles can be used to enhance vapor compression system performance in the refrigeration range of compressor operation. Pressure ratios in such systems are high and benefits in efficiency are sufficiently large to justify increased cost in circuit complexity.
In air conditioning operating range systems, however, the pressure ratio is much lower than in typical refrigeration systems, and this makes less desirable the use of economizer cycles and the like in such systems due to minimal return on increased cost and complexity.
It is clear that the need remains for enhanced system efficiency in air conditioning operating range systems.
It is therefore the primary object of the present invention to provide performance enhancement of vapor compression systems in connection with air conditioning operating range systems.
Other objects and advantages of the present invention will appear hereinbelow.
In accordance with the present invention, the foregoing objects and advantages have been readily attained.
According to the invention, in an air conditioning system comprising a compressor, a condenser, and an evaporator, a process is provided which comprises the steps of feeding discharged refrigerant from said compressor to said condenser so as to provide a condensed refrigerant flow; splitting said condensed refrigerant flow into a main flow and an auxiliary flow wherein said auxiliary flow comprises between about 8 and about 12% wt. of total mass flow rate of said condensed refrigerant flow; reducing temperature and pressure of said auxiliary flow so as to provide an economizer flow; passing said economizer flow and said main flow through a heat exchanger so as to provide a sub-cooled main flow and an economizer discharge flow; feeding said economizer discharge flow to said compressor; and feeding said sub-cooled main flow through said evaporator to said compressor.
In further accordance with the invention, heat exchange with economized refrigerant flow can be carried out for multiple circuits in single heat exchangers, with one or more economizer flow circuits and with flow through the heat exchanger being carried out in parallel and/or in sequence. Further, with multiple circuits, economized and non-economized circuits can be combined.
Thus, in further accordance with the invention, in a multiple circuit air conditioning system comprising at least two circuits each including a compressor, a process is provided which comprises the steps of operating each compressor of said at least two circuits so as to produce at least two discharged refrigerant flows; feeding said at least two discharged refrigerant flows to condensing means for producing at least two condensed refrigerant flows; splitting a condensed refrigerant flow from at least one circuit of said circuits to obtain an auxiliary flow and at least two main condensed refrigerant flows; reducing temperature and pressure of said auxiliary flow so as to provide an economizer flow; passing said economizer flow and said at least two main condensed refrigerant flows through a heat exchanger so as to provide at least two sub-cooled main flows and an economizer discharge flow; feeding said economizer discharge flow to said compressor of said at least one circuit; and feeding said at least two sub-cooled main flows through evaporator means to said compressor of said at least two circuits.
A multiple circuit air conditioning system is also provided, which comprises a first circuit including a series connection of a first compressor, a first condenser, a heat exchanger and evaporator means; a second circuit including a series connection of a second compressor, a second condenser, said heat exchanger and said evaporator means; and at least said first circuit including an economizer circuit including a series connection of said first compressor, said first condenser, an expander, and said heat exchanger.